The present invention relates to diffusion coating processes. In particular, the present invention relates to maskant free diffusion coating processes of selected areas.
Diffusion coating processes, such as diffusion aluminide coating processes, are used to apply protective coatings over metal components in a variety of industries. For example, turbine engine components are typically diffusion coated with aluminum based alloys to form aluminide coatings that protect the underlying engine components from oxidation and other environmental elements. During a diffusion coating process, it is desirable to selectively coat portions of a metal component, while allowing other portions to remain uncoated.
One technique for selectively coating a metal component involves the use of maskant film which is applied over a desired location. Another technique is to cover portions of the component with maskant powder that protects the covered portions from the coating vapor.
Following coating, the maskant needs to be removed from the component, typically by abrasive means, and the surface washed and dried. These steps add to the process time and substantially reduce the throughput of metal components.